Apparatus for making nonwoven fabrics having raised portions

ABSTRACT

A topographical support member and a method of forming a topographical support member for use in producing nonwoven fabrics with raised portions, especially intaglio and slub type portions. The topographical support member comprises a body having a top surface including a first micro-sized topographical pattern and a pattern of apertures extending through the body. At least one macro-sized region recessed below the top surface is provided. The micro-sized pattern produces a background portion of the fabric and the macro-sized recessed regions produce the raised portions of the fabric. Multiple levels may be provided in the macro-sized region to produce multiple level raised portions.

RELATED APPLICATIONS

This application is related to commonly assigned U.S. patent applicationSer. No. 08/307,203, filed Sept. 16, 1994, now U.S. Pat. No. 5,585,017,entitled DEFOCUSED LASER DRILLING PROCESS FOR MAKING FABRIC FORMINGDEVICE (attorney docket 9332Z), commonly assigned U.S. patentapplication Ser. No. 08/574,252, filed Dec. 18, 1995, pending, entitledFOCUSED RASTER SCAN DRILLING (attorney docket 9332ZY), which is acontinuation-in-part application of Ser. No. 08/307,203, now U.S. Pat.No. 5,585,017, and commonly assigned U.S. patent application Ser. No.08/308,001, filed Sep. 16, 1994, pending, entitled NONWOVEN FABRICSHAVING RAISED PORTIONS (attorney docket 9372).

RELATED APPLICATIONS

This application is related to commonly assigned U.S. patent applicationSer. No. 08/307,203, filed Sept. 16, 1994, now U.S. Pat. No. 5,585,017,entitled DEFOCUSED LASER DRILLING PROCESS FOR MAKING FABRIC FORMINGDEVICE (attorney docket 9332Z), commonly assigned U.S. patentapplication Ser. No. 08/574,252, filed Dec. 18, 1995, pending, entitledFOCUSED RASTER SCAN DRILLING (attorney docket 9332ZY), which is acontinuation-in-part application of Ser. No. 08/307,203, now U.S. Pat.No. 5,585,017, and commonly assigned U.S. patent application Ser. No.08/308,001, filed Sep. 16, 1994, pending, entitled NONWOVEN FABRICSHAVING RAISED PORTIONS (attorney docket 9372).

BACKGROUND OF THE INVENTION

Traditional fabrics have, for centuries, been decorated and had theirsurface texture modified by embroidery and other needle arts.Originally, this process was obtained through tedious hand labor,painstakingly applying fine stitches that had the cumulative effect ofbuilding up a region of the background fabric according to someparticular pattern. The resulting product had a base fabric, comprisedof threads or yarns, woven or knitted according to some pattern, araised region formed by a collection of threads in some stitch pattern,and an overall pattern of these raised regions determined by theirrespective size, shape, orientation and placement. While rich inappearance, these products were complicated to create and costly toproduce.

Most nonwoven fabrics are flat and visually uninteresting. In someinstances, nonwoven fabrics are embossed or printed with some sort ofdesign to provide visual interest. In other instances, nonwoven fabricsare provided with an integral pattern during the course of theirmanufacture. Those having an integral pattern of their own fall into twocategories:

1) Apertured fabrics--where a pattern is created by a network of bundledfiber segments surrounding apertures or holes; or

2) Weight patterned fabrics--fabrics that achieve a visual effect byconcentrating fibers into regions of higher basis weight to increaseopacity relative to the lower basis weight regions which are moretranslucent.

It is important to differentiate between basis weight and density."Basis weight" is the weight of a unit area of fibrous web or fabric orportion thereof being characterized. Basis weight has also been called"area density" in some prior art patents. The term "density" is theweight of a unit volume of a fibrous web or fabric or portion thereofbeing characterized. "Density" has also been called "volume density" insome prior art patents. Typical embossing processes create regions ofhigher density without altering the basis weight. Traditional nonwovenpatterning processes produce regions of varying basis weight, whilemaintaining substantially uniform density.

The prior art nonwoven fabrics made with these known patterningprocesses do not have clear, well defined raised portions and thereforethe desired patterns are difficult to see. In addition, the raisedportions of prior art embossed nonwoven fabrics are not dimensionallystable and their raised portions lose their three-dimensional structurewhen stressed, as for example, when they are handled or laundered.

Processes for making nonwoven fabrics have been known for many years. Inone process, a fiber batt or web is treated with water streams to causethe fiber to entangle with each other and provide some strength in thebatt. Many methods have been developed for treating fiber batts in thismanner in an attempt to duplicate the physical properties and appearanceof woven fabrics.

U.S. Pat. Nos. 5,098,764 and 5,244,711 disclose the use of a supportmember in one such method of producing nonwoven fabrics. The supportmembers have a topographical feature configuration as well as an arrayof apertures. In this process, a starting web of fiber is positioned onthe topographical support member. The support member with the fibrousweb thereon is passed under jets of high pressure fluid, typicallywater. The jets of water cause the fiber to intertwine and interentanglewith each other in a particular pattern, based on the topographicalconfiguration of the support member.

The pattern of topographical features and apertures in the supportmember is critical to the structure of the resulting nonwoven fabric. Inaddition, the support member must have sufficient structural integrityand strength to support a fibrous web while fluid jets rearrange thefibers and entangle them in their new arrangement to provide a stablefabric. The support member must not under go any substantial distortionunder the force of the fluid jets. Also, the support member must havemeans for removing the relatively large volumes of entangling fluid soas to prevent "flooding" of the fibrous web, which would interfere witheffective entangling. Typically, the support member includes drainageapertures which must be of a sufficiently small size to maintain theintegrity of the fibrous web and prevent the loss of fiber through theforming surface. In addition, the support member should be substantiallyfree of burrs, hooks or the like irregularities that could interferewith the removal therefrom of the entangled fabric. At the same time,the support member must be such that fibers of the fibrous web beingprocessed thereon are not washed away under the influence of the fluidjets.

SUMMARY OF THE INVENTION

The present invention is directed to topographical support members andmethods of making them. These topographical support members can be usedto make nonwoven fabrics having a fibrous background portion in oneplane thereof and raised fibrous portions in another plane thereof.There may be two types of raised portions. The basis weight of the firsttype of raised portion is substantially the same as the basis weight ofthe background portion of the nonwoven fabric. The basis weight of thesecond type of raised portion is greater than the basis weight of thebackground portion.

On type of nonwoven fabric which can be made with support members of thepresent invention comprises a background portion and at least one raisedportion. The background portion is located in and defines a first planeof the nonwoven fabric. The raised portion of the nonwoven fabric islocated in a second plane which is above and parallel to the firstplane. The raised portion is joined to the background portion by afibrous transition region. In this specific nonwoven fabric, the basisweight of the raised portion is substantially the same as the basisweight of the background portion. The density of the background portionand the density of the raised portion are substantially the same. Araised portion whose basis weight is substantially the same as the basisweight of the background portion is sometimes referred to as an"intaglio" portion.

Another type of nonwoven fabric which can be made with support membersof the present invention also comprises a background portion and atleast one raised portion. As was the case with the first nonwovenfabric, the background portion is located in and defines a first planeof the nonwoven fabric and the raised portion is located in a secondplane which is above and parallel to the first plane. As was the casewith the first nonwoven fabric, the raised portion is joined to thebackground portion by a fibrous transition region. In the case of thesecond type of nonwoven fabric however, the basis weight of the raisedportion is greater than the basis weight of the background portion. Thedensity of the raised portion of this second nonwoven fabric issubstantially the same as the density of the background portion. Araised portion whose basis weight is greater than the basis weight ofthe background portion is sometimes referred to as a "slub" portion.

Yet another type of nonwoven fabric which can be made with supportmembers of the present invention, comprises a background portion, atleast one first raised portion, and at least one second raised portion.As was the case with the first and second nonwovens discussed above, thebackground portion is located in and defines a first plane of thenonwoven fabric. The first raised portion is located in a plane which isabove and parallel to the first plane. Similarly the second raisedportion is located in a plane which is above and parallel to the firstplane. Each of the first and second raised portions is joined to thebackground portion by a fibrous transition region. In this thirdnonwoven fabric, the basis weight of the first raised portion issubstantially the same as the basis weight of the background portion,while the basis weight of the second raised portion is greater than thebasis weight of the background portion. In other words, in this thirdtype of nonwoven fabric, the nonwoven fabric has one or more firstraised portions which are sometimes referred to as "intaglio" portionsand one or more second raised portions which are sometimes referred toas "slub" portions. It is not necessary that the first raised portionand the second raised portion be in the same plane; rather the firstraised portion may be in a plane which is above the plane of thebackground portion and the second raised portion may be in a plane whichis above the plane of the first raised portion.

In the process of forming nonwoven fabrics using the topographicalsupport members of the present invention, a web or layer of fibers or alightly entangled fibrous web is placed on a foraminous forming plate ortopographical support member comprising an essentially planar backgroundsurface with at least one relatively wide recessed region significantlydisplaced from the background surface of the forming plate. Typically,the support member comprises a multiplicity of recessed regions,positioned as depressions in some predetermined array, that will form adesired pattern of raised portions on the nonwoven fabric. Fluid forces,in the form of streams of water, are applied to the upper surface of thestarting fibrous web or layer of fibers. Initially, these fluid forces"mold" the starting web to the three dimensional support member; as theprocess of applying fluid forces continues, the fibers are entangled andlocked together so as to provide a nonwoven fabric comprising abackground portion and one or more raised portions which are permanentlypositioned with respect to one another.

In an alternative embodiment, the topographical support member has arelatively narrow recessed region displaced from the planar backgroundsurface of the forming plate.

The present invention is directed to a topographical support member anda method for forming a topographical support member for producingnonwoven fabrics having raised portions. The support members of thepresent invention comprise a body portion having a top surface includinga first micro-sized topographical pattern and a plurality of aperturesthrough its thickness. The body portion further comprises at least onemacro-sized region disposed below said top surface. The micro-sizedpattern produces the background portion of the nonwoven fabric. Themacro-sized region produces raised portions of the fabric conforming tothe shape and depth of the macro-sized region. The macro-sized recessedregion preferably has the same topographical pattern as the top surfaceof the support member, however, the regions may have a different patternor no pattern. In addition, the macro-sized region may include a majorsurface recessed a first depth below the top surface and one or moreminor surfaces recessed at depths different from the first depth. Forexample, one minor surface surrounding the major surface may be providedthat is recessed at a depth below the first depth and has a diameter ora cross-sectional width substantially less than the width of the majorsurface.

The topographical pattern comprising the top surface of the supportmember is preferably produced by a laser drilling process. The laserdrilling process produces a plurality of peaks, valleys and apertures inthe top surface of the support members. The macro-sized regions, formedby a laser ablation process, have a cross-sectional width larger thanthe repeat spacing of the repeating pattern.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top plan view of one nonwoven fabric which can be madeusing a support member of the present invention;

FIG. 1B is another nonwoven fabric which can be made using a supportmember of the present invention;

FIG. 1C is a top plan view of a third nonwoven fabric which can be madeusing a support member of the present invention;

FIG. 2 is a photomicrograph, in plan view, of a portion of a nonwovenfabric made using a support member of the present invention.

FIG. 2A is a perspective view of the cross-sectional view taken alongline 2A--2A of FIG. 2.

FIG. 2B is a perspective view of the cross-sectional view taken alongline 2B--2B of FIG. 2.

FIG. 3 is a photomicrograph of a cross-sectional view taken along Line2A--2A of FIG. 2.

FIG. 4 is a photomicrograph of a cross-sectional view taken along Line4--4 of FIG. 2.

FIG. 5 is a cross-sectional view, greatly enlarged, of one type ofraised portion in a nonwoven fabric made with a support member of thepresent invention.

FIG. 6 is a photomicrograph, in plan view, of a second type of raisedportion in a nonwoven fabric made with a support member of the presentinvention.

FIG. 7 is a photomicrograph of a cross-sectional view taken along Line7--7 of FIG. 6.

FIG. 8 is an idealized sketch of the cross-sectional view shown in FIG.7.

FIG. 9 is a block diagram of the steps of the process for makingnonwoven fabrics using support members of the present invention.

FIGS. 10, 11 and 12 are diagrammatic views of three types of apparatusfor producing nonwoven fabrics using support members of the presentinvention.

FIG. 13 is a perspective view, with parts in cross-section, of thatportion of a topographical support member used to produce one backgroundportion of a nonwoven fabric.

FIG. 14A is a sketch in cross-section showing one type of recessedregion in a topographical support member of the present invention.

FIG. 14B is a sketch in cross-section showing a different type ofrecessed region in a topographical support member of the presentinvention.

FIG. 15 is a sketch, in cross-section, of a nonwoven fabric made usingthe support member of FIG. 14B.

FIG. 16 is a diagrammatic view of an apparatus for forming topographicalsupport members of the present invention.

FIG. 17A is a bit map of the pattern used to create the support memberused to produce the nonwoven fabric 10C of FIG. 1C.

FIG. 17B is a bit map, greatly enlarged, of the rectangular region 301of FIG. 17A.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, FIG. 1A is a top plan view of onenonwoven fabric which can be made using a support member of the presentinvention. Nonwoven fabric 10A includes a background portion 12 and atleast one integrally formed raised portion 16. Three such raisedportions, illustrated as the letters "J", "S" and "K", are shown in FIG.1A. Nonwoven fabric 10 comprises a plurality of generally staple lengthfibers which may be, for example, cotton, rayon or polyester, or blendsthereof. Background portion 12 is located in and defines a first planeof nonwoven fabric 10A. Raised portions 16 are located in a plane whichis above and parallel to the first plane. Raised portions 16 are joinedto the background portion 12 by a fibrous transition region which willbe described in greater detail hereinafter. In nonwoven fabric 10A ofFIG. 1A, the basis weight of the raised portions 16 is the same as thebasis weight of the background portion 12. The density of raisedportions 16 is substantially identical to the density of backgroundportion 12.

Referring now to FIG. 1B, there is illustrated another type of nonwovenfabric which can be made using a support member of the presentinvention. Nonwoven fabric 10B is also made of a plurality of staplelength fibers and has a background portion 12 and an integrally formedraised portion 18 which, in top plan view, is generally rectangular inshape. As was the case with nonwoven fabric 10A, background portion 12of nonwoven fabric 10B is located in and defines a first plane ofnonwoven fabric 10B. As was also the case with nonwoven fabric 10A,raised portion 18 in nonwoven fabric 10B is joined to its backgroundportion 12 by a fibrous transition region which, as mentioned above,will be described hereinafter. The basis weight of raised portion 18 innonwoven fabric 10B is greater than the basis weight of backgroundportion 12 to which it is joined. Thus it will be appreciated thatwhereas raised portions 16 comprising nonwoven fabric 10A have the samebasis weight as its background portion 12, the basis weight of theraised portion 18 of nonwoven fabric 10B has a basis weight which isdifferent from the basis weight of its background portion 12.

Yet another nonwoven fabric which can be made using a support member ofthe present invention is shown in top plan view in FIG. 1C of thedrawings. Nonwoven fabric 10C is made from a plurality of staple lengthfibers as was the case with nonwoven fabrics 10A and 10B. Nonwovenfabric 10C has a background portion 12 which is located in and defines afirst plane of the nonwoven fabric and, in this respect, is the same asthe earlier mentioned nonwoven fabrics. Nonwoven fabric 10C comprisesfirst raised portions 16 shown as the letters "J", "S", and "K" in FIG.1C. Nonwoven fabric 10C further comprises a raised portion 18, enclosingthe three letters "J", "S" and "K". The raised portions 16 of nonwovenfabric 10C correspond to raised portions 16 of nonwoven fabric 10A. Theraised portion 18 of nonwoven fabric 10C corresponds to raised portions18 of nonwoven fabric 10B. It will be understood that raised portions 16of nonwoven fabric 10C have a basis weight which is substantiallyidentical to the basis weight of background portion 12 of the fabric. Onthe other hand, raised portion 18 comprising nonwoven fabric 10C has abasis weight which is greater than the basis weight of its backgroundportion 12. In nonwoven fabric 10C, the background portion 12, the firstraised portions 16, and the second raised portion 18, have substantiallyidentical densities.

Background portions 12 of nonwoven fabrics 10A, 10B and 10C are the samein each instance. This background portion 12 has a tricot-like patternand appearance but it will be understood that the background portion mayhave different patterns and appearances. In the specific case ofnonwoven fabric 10A, raised portions 16 and background portion 12 havethe same tricot-like pattern and appearance. Similarly, the raisedportion 18 of nonwoven fabric 10B has the same tricot-like appearance asbackground portion 12. Finally, background portion 12, first raisedportions 16, and second raised portion 18 comprising nonwoven fabric 10Call have the same tricot-like pattern and appearance. It should beunderstood, however, that first raised portions 16, second raisedportion 18 and background portion 12 of nonwoven fabric 10C may havediffering patterns and appearances.

FIG. 2 is a photomicrograph at 15× magnification and in top plan view ofa portion of a nonwoven fabric 10D which is similar to nonwoven fabric10A of FIG. 1A. Nonwoven fabric 10D comprises a tricot-like backgroundportion 12 and a raised portion 16 which also has a tricot-like pattern.It will be understood that only a portion of raised fibrous portion 16is seen in FIG. 2. Raised portion 16 is joined to background portion 12by fibrous transition regions 22 and 24. As can be seen by reference toFIG. 2, fibrous transition region 22 runs in the horizontal direction onone side of raised portion 16, said horizontal direction being thecross-machine direction of nonwoven fabric 10D. Fibrous transitionregion 24 runs in the longitudinal direction on another side of raisedportion 16, said longitudinal direction being the machine direction ofnonwoven fabric 10D. Fibrous transition region 22 meets fibroustransition region 24 at an angle of about 90° at a corner 23 of raisedportion 16. The fibrous structures of transition regions 22 and 24 aresubstantially the same. As mentioned earlier herein, the basis weight ofraised portion 16 is substantially the same as the basis weight ofbackground portion 12.

FIG. 2A is a sketch showing nonwoven fabric 10D, a photomicrograph ofthe top surface of which is shown in FIG. 2. FIG. 2A, which is presentedin order to assist in the understanding of the fibrous structure ofnonwoven fabric 10D, is a perspective view of the cross-section takenalong line 2A--2A of FIG. 2. Referring to FIG. 2A, nonwoven fabric 10Dhas a fibrous background portion 12 and a fibrous raised portion 16,each of which is formed in a tricot-like pattern. Raised portion 16 isjoined to background portion 12 by a fibrous transition region 24 whichextends in the machine direction of fabric 10D. Fibrous transitionregion 24 comprises a fiber-poor region 30 and a fiber-rich region 32.Fiber-poor region 30 comprises a plurality of bundles 30a of fibersegments and these bundles 30a define a plurality of apertures 30b intransition region 24. The fiber segments comprising bundles 30a arehighly parallelized and some of these fiber segments are in a twistedconfiguration within the bundle. A majority of the bundles 30a aretwisted and turned upon themselves.

Fiber-rich region 32 comprises a plurality of fiber segments whichextend predominantly in the vertical direction of FIG. 2 whichcorresponds to the machine direction of nonwoven fabric 10D. The ends ofthese fiber segments can be seen in FIG. 2A where they are identified bynumeral 26. The basis weight of fiber-poor region 30 is less than thebasis weight of fiber-rich region 32 and is also less than the basisweight of both background portion 12 and raised portion 16. The basisweight of fiber-rich region 32 is greater than the basis weight of bothbackground portion 12 and raised portion 16. Bundles 30a in thefiber-poor region 30 are oriented generally transversely of fibroustransition region 24. The fiber segments comprising the fiber-richregion 32 are oriented generally longitudinally of transition region 24.

FIG. 2B is another sketch showing nonwoven fabric 10D. FIG. 2B is aperspective view of the cross-section taken along line 4--4 of FIG. 2.Referring to FIG. 2B, raised portion 16 is joined to background portion12 by a fibrous transition region 22 which extends in the cross machinedirection of fabric 10D. Transition region 22 comprises a fiber-poorregion 27 and a fiber-rich region 28 analogous, respectively, tofiber-poor region 30 and fiber-rich region 32 of fibrous transitionregion 24 discussed above. Fiber-poor region 27 comprises a plurality ofbundles 27a of fiber segments and these bundles 27a define a pluralityof apertures 27b in transition region 22. The fiber segments comprisingbundles 27a are very highly parallelized and some of these fibersegments are in a twisted configuration within the bundle. A minority ofthe bundles 27a are twisted and turned upon themselves. This is incontrast to the structure of fiber-poor region 30 of transition region24 previously discussed in which a majority of bundles 30a are twistedand turned upon themselves. Fiber-rich region 28 comprises a pluralityof fiber segments which extend predominantly in the horizontal directionof FIG. 2 which corresponds to the cross-machine direction of nonwovenfabric 10D. The ends of these fiber segments can be seen in FIG. 2Awhere they are identified by numeral 29. The basis weight of fiber-poorregion 27 is less than the basis weight of fiber-rich region 28 and isalso less than the basis weight of both background portion 12 and raisedportion 16. The basis weight of fiber-rich region 28 is greater than thebasis weight of both background portion 12 and raised portion 16.Bundles 27a in the fiber-poor region 27 are oriented generallytransversely of fibrous transition region 22. The fiber segmentscomprising the fiber-rich region 28 are oriented generallylongitudinally of transition region 22.

FIG. 3 is a photomicrograph of nonwoven fabric 10D taken along line2A--2A of FIG. 2. FIG. 3 shows raised portion 16 joined to backgroundportion 12 by transition region 24. The fiber-rich region 32 is seenadjacent fiber-poor region 30. The large number of fiber ends 26 infiber-rich region 32 demonstrates the high level of parallelism of thefiber segments in the fiber-rich region.

FIG. 4 is a photomicrograph of fibrous transition region 22 of nonwovenfabric 10D taken along line 4--4 of FIG. 2. Numeral 28 indicates thefiber-rich region of transition region 22, while numeral 27 indicatesthe fiber-poor region. It can be seen that the fiber segments infiber-poor region 27 are highly parallelized. In general, there is lessparallelism of fibers in fiber-rich region 28 than there is in thecorresponding region 32 shown in FIG. 3.

FIG. 5 is an artistic representation of a cross-sectional view showingraised portion 16 joined to background portion 12 by transition region24. Transition region 24 comprises a fiber-poor region 30 and afiber-rich region 32. As mentioned earlier, fiber-rich region 32 has ahigher basis weight than fiber-poor region 30. The basis weight ofraised portion 16 lying between fiber-rich regions 32 in FIG. 5 issubstantially uniform and is substantially equal to the basis weight ofbackground portion 12.

FIG. 6 is a photomicrograph enlargement in plan view of a nonwovenfabric similar to nonwoven fabric 10B of FIG. 1B. The background portion12, on either side of the raised portion 18 has a tricot-likemicro-sized pattern. In this embodiment, the tricot-like pattern is alsopresent on the top surface of raised portion 18. The fibers comprisingraised portion 18 are in bundles that are twisted and turned upon eachother and are substantially parallel to each other in the longitudinaldirection of the raised portion.

As indicated earlier herein, the basis weight of raised portion 18 isgreater than the basis weight of background portion 12. The density ofraised portion 18 is substantially equal to the density of backgroundportion 12. Raised portion 18 is connected to background portion 12 by afibrous transition region 34 which has a lower basis weight than thebasis weight of background portion 12.

FIG. 7 is a photomicrograph of the nonwoven fabric of FIG. 6 taken alongline 7--7 of FIG. 6. The large number of fiber ends 36 seen in raisedportion 18 demonstrates that the fiber segments in the raised portion 18extend in the longitudinal direction of the raised portion.

FIG. 8 is an artistic representation of a cross-sectional view showingraised portion 18 joined to background portion 12 by transition region34. It will be seen that the bottom surface 18a of raised portion 18 isessentially co-planar with the bottom surface 12a of background portion12. The uppermost surface 18b of raised portion 18 extends above theupper surface 12b of background portion 12.

FIG. 9 is a block diagram showing the various steps in the process ofproducing nonwoven fabrics using a support member of the presentinvention. The first step in this process is to position a web of fiberson a topographical support member (Box 1). The fibrous web is presoakedor wetted out with water while on this support member (Box 2) to ensurethat as it is being treated it will remain on the support member. Thesupport member with the fibrous web thereon is passed under a series oforifices from each of which a fluid, such as water, is ejected underhigh pressure and directed toward the upper surface of the fibrous web,i.e., that surface of the web which is out of contact with thetopographical support member (Box 3). The preferred fluid is water. Thewater is transported away from the support member, preferably using avacuum (Box 4). The fibrous web is de-watered (Box 5). The de-wateredformed fabric is removed from the support member (Box 6). The formedfabric is passed over a series of drying drums to dry the fabric (Box7). The fabric may then be finished or otherwise processed as desired(Box 8).

FIG. 10 is a schematic representation of one type of apparatus forproducing nonwoven fabrics using support members of the presentinvention. In this apparatus, a foraminous conveyor belt 70 movescontinuously about two spaced apart rotatable rolls 71 and 72. The beltis driven so that it can be reciprocated or moved in either a clockwiseor counterclockwise direction. A water ejecting manifold 74 is placedabove the upper reach 73 of belt 70. This manifold has a plurality ofvery fine diameter holes or orifices. The diameter of the orifices isabout 0.007 inch and there are about 30 such holes per lineal inch.Water is supplied to manifold 74 under pressure and is ejected from theorifices in the form of substantially columnar, non-diverging jets orstreams. A topographical support member 75 is placed on top of belt 70and a web 76 of fibers is placed on top of the topographical supportmember. A suction manifold 77 is placed directly beneath water manifold74, but under upper reach 73 of belt 70. This suction manifold aids inremoving the water ejected from manifold 74 so as to prevent flooding offibrous web 76. Water delivered to the manifold at a predeterminedpressure is ejected from the orifices of the manifold in the form ofsubstantially columnar streams or jets and impinges on the upper surfaceof fibrous web 76. The distance from the lower surface 74a of manifold74 to the upper surface of web 76 to be processed is sufficiently smallso as to insure that the water jets which issue from the orifices ofmanifold 74 contact the upper surface of fibrous web 76 in theaforementioned substantially columnar, non-diverging form. This distancemay vary but typically is about 0.75 inch. The water jets pass throughthe fibrous web, then through drain holes provided in the topographicalsupport member. Spent processing water is removed through the suctionmanifold. As may be appreciated, the topographical support member withthe fibrous web thereon may be passed under the manifold a number oftimes as desired to produce fabrics in accordance with the presentinvention.

FIG. 11 depicts an apparatus for continuously producing nonwoven fabricsusing support members in accordance with the present invention. Theapparatus of FIG. 11 includes a conveyor belt 80 which actually servesas the topographical support member in accordance with the presentinvention. The belt is continuously moved in a counterclockwisedirection about a pair of spaced-apart rollers as is well known in theart. Disposed above belt 80 is a fluid ejecting manifold 79 connecting aplurality of lines or groups 81 of orifices. Each group has one or morerows of very fine diameter orifices, each about 0.007 inch in diameterwith 30 such orifices per inch. Water is supplied to the groups 81 oforifices under a predetermined pressure and is ejected from the orificesin the form of very fine, substantially columnar, non-diverging streamsor jets of water. The manifold is equipped with pressure gauges 88 andcontrol valves 87 for regulating the fluid pressure in each line orgroup of orifices. Disposed beneath each orifice line or group is asuction box 82 for removing excess water, and to keep the area fromundue flooding. The fiber web 83 to be formed into the fabric of thepresent invention is fed to the topographical support member conveyorbelt. Water is sprayed through an appropriate nozzle 84 onto the fibrousweb to pre-wet the incoming web 83 and aid in controlling the fibers asthey pass under the fluid ejecting manifolds. A suction slot 85 isplaced beneath this water nozzle to remove excess water. Fibrous webpasses under the fluid ejecting manifold in a counter clockwisedirection. The pressure at which any given group 81 of orifices isoperated can be set independently from the pressure at which any of theother groups 81 of orifices is operated. Typically, however, the group81 of orifices nearest spray nozzle 84 is operated at a relatively lowpressure, e.g. 100 psi. This assists in settling the incoming web ontothe surface of the support member. As the web passes in thecounterclockwise direction in FIG. 11, the pressures at which the groups81 of orifices are operated is usually increased. It is not necessarythat each succeeding group 81 of orifices be operated at a pressurehigher than its neighbor in the clockwise direction. For example, two ormore adjacent groups 81 of orifices could be operated at the samepressure, after which the next succeeding group 81 of orifices (in thecounterclockwise direction) could be operated at a different pressure.Very typically, the operating pressures at the end of the conveyor beltwhere the web is removed are higher than the operating pressures wherethe web is initially fed into the conveyor belt. Though six groups 81 oforifices are shown in FIG. 11, this number is not critical, but willdepend on the weight of the web, the speed, the pressures used, thenumber of rows of holes in each group, etc. After passing between thefluid ejecting manifold and the suction manifolds, the now formednonwoven fabric is passed over an additional suction slot 86 to removeexcess water. The distance from the lower surfaces of the groups 81 oforifices to the upper surface of fibrous web 83 typically ranges fromabout 0.5 inch to about 2.0 inches; a range of about 0.75 inch to about1.0 inch is preferred. It will be apparent that the web cannot be spacedso closely to the manifold that the web contacts the manifold. On theother hand, if the distance between the lower surfaces of the orificesand the upper surface of the web is too great, the fluid streams willlose energy and the process will be less efficient.

A preferred apparatus for producing nonwoven fabrics using supportmembers of the present invention is schematically depicted in FIG. 12.In this apparatus, the topographical support member is a rotatable drum90. The drum rotates in a counterclockwise direction. Drum 90 may be acontinuous cylindrical drum or may be made of a plurality of curvedplates 91, disposed so as to form the outer surface of the drum. Ineither case, the outer surface of the drum 90 or the outer surfaces ofthe curved plates 91 comprises the desired topographical supportconfiguration. Disposed about a portion of the periphery of the drum isa manifold 89 connecting a plurality of orifice strips 92 for applyingwater or other fluid to a fibrous web 93 placed on the outside surfaceof the curved plates. Each orifice strip may comprise one or more rowsof very fine diameter holes or apertures of the type mentioned earlierherein. Typically, the apertures are approximately 5/1000 of an inch to10/1000 of an inch in diameter. There may be as many as 50 or 60 holesper inch or more if desired. Water or other fluid is directed throughthe rows of orifices. In general, and as explained above, the pressurein each orifice group is typically increased from the first group underwhich the fibrous web passes to the last group. The pressure iscontrolled by appropriate control valves 97 and is monitored by pressuregauges 98. The drum is connected to a sump 94 on which a vacuum may bepulled to aid in removing water and to keep the area from flooding. Inoperation, the fibrous web 93 is placed on the upper surface of thetopographical support member before the water ejecting manifold 89 asseen in FIG. 12. The fibrous web passes underneath the orifice stripsand is formed into a nonwoven fabric in accordance with the presentinvention. The formed fabric is then passed over a section 95 of theapparatus 95 where there are no orifice strips, but vacuum is continuedto be applied. The fabric after being de-watered is removed from thedrum and passed around a series of dry cans 96 to dry the fabric.

In order to create the raised portions in nonwoven fabrics, a layer offibers or a lightly entangled web is placed on a foraminous supportmember comprising a top surface having a topographical pattern and asecond surface displaced from the top surface of the support member. Thetop surface creates the background portion and the second surfacecreates the raised portion of the fabric.

The top surface has a structure which minimizes lateral movement of thefibers of the starting fibrous web that would undesirably create areasof high and low fiber concentration. If there is excessive lateralmovement of the fibers during processing, the resulting nonwoven fabricmay have thin spots or regions devoid of fibers.

An example of a topographical support member for making a pattern in thebackground portion of a nonwoven fabric is shown in FIG. 13. The supportmember 102 comprises a body 100 having a top surface 103 and bottomsurface 104. Disposed in a predetermined pattern across top surface 103is an array of peaks 105 separated by valleys 106. A plurality ofdrainage apertures 107 extends through the thickness of the supportmember are disposed in a pattern in the member 102. In this embodiment,each drainage aperture 107 is surrounded by a cluster of six peaks 105and six valleys 106.

The drainage apertures 107 are tapered, or "bell mouthed", having alarger diameter at the top surface 103 of the support member than thebottom surface 104. The angle 111 formed by the taper must be controlledrelative to the thickness 112 of the support member 102 to produce theintended result. For example, if the angle is too great, the aperturewill be too small and therefore insufficient drainage will be provided.If the angle is too small, there will be very few or no peaks andvalleys in the support member.

The center-to-center spacing, S, of adjacent apertures in the repeatingpattern is of similar importance. The peaks 105 and valleys 106 arecreated by the intersection of the tapered, somewhat conical apertures107. If the center-to-center spacing, S, of the apertures were greaterthan the major diameter of aperture 107 at the top surface 3, nointersection would result, and the member would be a smooth, flat topsurface with conical apertures disposed throughout. When thecenter-to-center spacing of adjacent apertures is less than the aperturediameters measured along that center-to-center line, the conicalsurfaces intersect forming a valley. The support member of FIG. 13 willproduce a tricot-like pattern in the background portion of a nonwovenfabric. Any pattern may be employed to form the design of the backgroundportion of the nonwoven fabric.

The second surface of the foraminous support member is comprised of aplurality of recesses that will create the raised portions in the finalfabric. FIG. 14A is a cross-sectional view of a support member 122having a top surface 123 and a recessed region 121 comprising secondsurface 124. Apertures 127 are approximately normal to the supportmember, and extend fully from the top surface 103 to the bottom surface104. The apertures must be of adequate size and number to remove theexcess fluid during entangling and prevent "excessive flooding" of thesupport member surface during entangling.

It will be apparent to one skilled in the art that recessed region 121must be of sufficient size so as to provide a clearly defined raisedportion in the finished nonwoven fabric. For example, the specificsupport member 102 shown in FIG. 13 has a repeating pattern comprising asingle aperture 107 surrounded by six peaks 105. Apertures 107 in member102 have a center line-to-center line spacing of S. The narrowestdimension of recessed region 121 must be greater than the centerline-to-center line spacing, S. If the narrowest dimension of recessedregion 121 is less than center line-to-center line spacing S, the raisedregion will not be well defined or may not exist at all in the finalnonwoven fabric. In a specific embodiment of support member 122, whichhas been used to make nonwoven fabrics of the present invention, thewidth of the recessed region 121 is about 11 times the centerline-to-center line spacing, S, of apertures 107. The recessed surfacesshould be deep enough to be clearly discernable as a different level,may have multiple levels, and may be curved as well as planar. Therecessed second surface 121 of member 122 may have the same pattern astop surface 123, or a different pattern.

The top surface of the support member is provided with sufficienttexture to control the movement of fibers, preventing "washed out" areasyet allowing sufficient mobility for the web of fibers to arrangethemselves in the recesses and interlock under the influence of thefluid jets. With an appropriately aggressive pattern of holes, noadditional texture is required. Usually, however, some texture iscreated in this surface to provide better control of fiber movement andimpart visual interest to the final fabric.

A transition region is evident between the two levels. A thinning of thefiber concentration at the edge of the background occurs, with acorresponding increase in fiber concentration near the edge of theraised portion. With a sample fabric averaging 2.19 oz./sq. yd., stripsof fabric 7/64" wide by 1/2" long were cut with the long dimensionparallel to the transition line, centered in the areas of highest andlowest fiber concentration. The weight ratio of heavy strips to lightstrips for four different patterns averaged 1.53:1. The result is that awide feature has a background portion basis weight about equal to theraised portion basis weight, but with this rather poorly definedtransition having light and heavy areas. To remedy this for largerfeatures, the preferred embodiment will have three or more distinct,essentially parallel surfaces, each at a different layer in thethickness of the backing member.

FIG. 14B shows a cross section of a topographical support member 128with top surface 123, recessed region 121, recessed surface 124, asecond recessed region 125, and bottom surface 126. Apertures 127 extendthrough the entire thickness of the support member.

A nonwoven fabric made using support member 122 comprises a backgroundportion 12, a raised portion 16 and a transition region 24 comprising afiber-poor region 30 and a fiber-rich region 32. The fiber-rich region32 of transition region 24 lies adjacent and is connected to theperiphery of raised portion 16. In this nonwoven fabric, there is adistinct and visually apparent boundary between the fiber-poor region 30and the background portion 12. However, the boundary between thefiber-rich region 32 and the periphery of the raised portion 16 is lessdistinct and less visually apparent. This latter boundary can be mademore distinct and more visually apparent by using the topographicalsupport member shown in FIG. 14B to make the nonwoven fabric. As seen inFIG. 14B, topographical support member 128 comprises a top surface 123,a recessed surface 124, a pair of second recessed regions 125, a bottomsurface 126 and a plurality of apertures 127 extending through itsthickness. A nonwoven fabric made with topographical support member 128is shown in cross-section in FIG. 15 of the drawings. There it will beseen that the nonwoven fabric comprises a background portion 12, araised portion 16 and a fibrous transition region 24 which joins thebackground portion and the raised portion. Transition region 24comprises a fiber-poor region 30 and a fiber-rich region 32 analogous tothose seen in FIG. 5. Whereas in the nonwoven fabric of FIG. 5, theupper surface of fiber-rich portion 32 is substantially coplanar withthe upper surface of raised portion 16, the upper surface of theanalogous fiber-rich region 32 of the nonwoven fabric shown in FIG. 15is in a plane which is above the plane of the upper surface of raisedportion 16. This is a result of the provision in support member 128 ofthe pair of second recessed regions 125. In the nonwoven fabric of FIG.15, the boundary between fiber-rich region 32 of transition region 24and the raised portion 16 is more distinct and more visually apparentthan in the case of the nonwoven fabric of FIG. 5. Additional recessedregions in the support member will provide additional raised portions inthe fabric. Multiple recessed surfaces may be provided in the supportmember, as desired, to create further corresponding raised portions inthe nonwoven fabric. It will be apparent that, in accordance with theteachings of the present invention, a support member can be providedwhich can be used to produce a modified version of the nonwoven fabricof FIG. 15 wherein the central region of raised portion 16 carries afurther raised portion projecting upwardly from the upper surfacethereof.

Referring again to FIG. 1B, there is shown a nonwoven fabric having araised portion 18 in the form of a rectangle. As already mentioned, thebasis weight of raised portion 18 is greater than that of backgroundportion 12. The nonwoven fabric of FIG. 1B can be made on a modificationof support member 128 shown in FIG. 14B. Such modified support memberwould comprise recessed region 125 arranged in the form of the desiredrectangle but would not, however, include recessed region 121 or itsrecessed surface 124.

Topographical support members of the present invention may be producedby processing a precursor support member workpiece having any desiredtopographical configuration on the apparatus shown in FIG. 16.

The desired precursor workpiece is mounted on an appropriate arbor, ormandrel 821 that fixes it in a cylindrical shape and allows rotationabout its longitudinal axis in bearings 822. A rotational drive 823 isprovided to rotate mandrel 821 at a controlled rate. Rotational pulsegenerator 824 is connected to and monitors rotation of mandrel 821 sothat its precise radial position is known at all times.

Parallel to and mounted outside the swing of mandrel 821 is one or moreguide ways 825 that allow carriage 826 to traverse the entire length ofmandrel 821 while maintaining a constant clearance to the top surface803 of tube 802. Carriage drive 833 moves the carriage along guide ways825, while carriage pulse generator 834 notes the lateral position ofthe carriage with respect to support member 802. Mounted on the carriageis focusing stage 827. Focusing stage 827 is mounted in focus guide ways828 and allows motion orthogonal to that of carriage 826 and provides ameans of focusing lens 829 relative to top surface 803. Focus drive 832is provided to position the focusing stage 827 and provide the focusingof lens 829.

Secured to focusing stage 827 is the lens 829, which is secured innozzle 830. Nozzle 830 has means 831 for introducing a pressurized gasinto nozzle 830 for cooling and maintaining cleanliness of lens 829.

Also mounted on the carriage 826 is final bending mirror 835, whichdirects the laser beam 836 to the focusing lens 829. Remotely located isthe laser 837, with optional beam bending mirrors 838 to direct the beamto final beam bending mirror 835. While it would be possible to mountthe laser 837 directly on carriage 826 and eliminate the beam bendingmirrors, space limitations and utility connections to the laser makeremote mounting far preferable.

When the laser 837 is powered, the beam 836 emitted is reflected firstoff beam bending mirror 838, then final beam bending mirror 835, whichdirects it to lens 829. The path of laser beam 836 is configured suchthat, if lens 829 were removed, the beam would pass through thelongitudinal center line of mandrel 821.

When focusing lens 829 passes beam 836, it concentrates the energy nearthe center of the beam. The rays are not bent through a single point,but rather a spot of small diameter. The point of smallest diameter issaid to be the focus or focal point. This occurs at a distance from thelens said to be the focal length. At lengths either shorter or greaterthan the focal length, measured spot sizes will be greater than theminimum.

A precursor support member comprising a predetermined topography and apredetermined pattern of openings therein is prepared or otherwiseobtained. One support member which is suitable as such a precursor isdisclosed in FIG. 3 of U.S. Pat. No. 5,098,764. This support member,identified by numeral 56 in FIG. 3 of the '764 patent, comprises rows ofpyramids 61 whose apices 65 are aligned in two directions perpendicularto each other. These pyramids have "sides" 66 and the spaces between thepyramids are called "valleys" 67. This support member also includes aplurality of holes or apertures 68 disposed in a pattern and extendingthrough the thickness of the support member. Several other topographicalsupport members are disclosed in U.S. Pat. No. 5,098,764 and all ofthese support members are suitable precursors for use in making supportmembers for practicing the present invention. Precursor support membersmust be constructed of materials which are suitable for processing bylaser ablation; acetal or acrylic materials are preferred materials ofconstruction. Specifics of the laser processing of polymeric materialshave been disclosed in commonly assigned co-pending U.S. patentapplication Ser. No. 08/307,203, filed Sep. 16, 1994, now U.S. Pat. No.5,585,017 the title of which is "Defocused Laser Drilling Process ForMaking Fabric Forming Device" and the disclosure of which is herebyincorporated by reference.

The support member illustrated in FIG. 13 of the accompanying drawingsis used as the precursor topographical support member from which isprepared a support member for making nonwoven fabric 10C shown in FIG.1C of the accompanying drawings. This precursor support member isdisclosed in FIG. 5 of copending U.S. patent application Ser. No.131,191, filed Sep. 13, 1993, pending the title of which is "TricotNonwoven Fabric" and the disclosure of which is hereby incorporated byreference. As disclosed in the aforementioned application, thisparticular support member can be used to make nonwoven fabrics with atricot-like surface appearance.

The process for laser drilling a precursor support member to provide asupport member of the present invention which can be used to producenonwoven fabric 10C of FIG. 1C will now be described. An initialfocusing step must be performed. The precursor support member shown inFIG. 13 is positioned on the mandrel 821, and the carriage drive 833 ismotored to place the focal point of the lens 829 in a non-drilledportion of the starting tube from which the precursor support member wasoriginally made. Typically, non-drilled portions are provided as amargin at each end of the support member; these non-drilled portionsprovide not only areas for trial engraving but also function as areinforcing means, thus providing structural integrity to the supportmember. The laser is pulsed briefly and the mandrel rotated slightlybetween pulses such that a series of small depressions is provided.

The focus stage 827 is then moved with respect to the mandrel centerline to change the focus position and another series of depressions isproduced. Typically a matrix of 20 columns of 20 depressions each isdrilled, with the focus stage being repositioned inbetween each pair ofcolumns. The depressions are examined microscopically, and the column ofsmallest depressions is identified. The position of the focus stage 827that produced this column of smallest diameter depressions defines thereference diameter for the precursor support member top surface 103 atwhich the beam is focused.

A desired pattern is selected, such as that in FIG. 17A. FIG. 17A is abit map of the pattern used to create the support member which wasultimately used to produce the nonwoven fabric 10C of FIG. 1C. FIG. 17Bis a bit map, greatly enlarged, of the rectangular region 301 of FIG.17A. As can be seen in FIG. 17B, the curved portion of the mirror imageof the letter "S" is not a smooth curve, but rather a series of tinystepped squares, or "pixels". Each of these pixels corresponds to aregion on the surface of the precursor support member to be engraved.The typical dimension of the support member surface corresponding to onepixel is 0.002 inch in each direction. The pixels that are colored blackcorrespond to regions that will be a depressed region in the finalsupport member, that is, regions where the laser will be turned on toremove material by ablation. The pixels that are white correspond toregions of the support member that should remain unaltered by thisprocess, and consequently are regions where the laser will be turnedoff. In this manner the pattern of FIG. 17A encodes the laser operatinginstructions to produce the image in the support member.

The pattern must be adjusted to produce an image of the intended size.If, for example, a depressed feature in the support member is desiredwith a length of one inch, and the above-mentioned scale is employed,the bit map must be created with that image being 500 pixels long.

A position is then selected for the first depressed region to be createdin the precursor support member. This must be defined for both thelongitudinal position (across the face of the precursor support member)and the circumferential position (around the circumference of theprecursor support member). This starting position corresponds to the topleft corner of the bit map in FIG. 17A of the accompanying drawings.Columns of pixels in the bit map correspond to regions disposed aroundthe circumference of the precursor support member. Rows of pixels in thebit map correspond to regions disposed across the face of the precursorsupport member.

If more than one depressed region is desired in the final supportmember, the initial corner location is established for each suchdepression. If desired, the computer control system can be configuredsuch that the number of repeats of a pattern in each direction(longitudinal and circumferential ) can be specified, and the computerwill determine the starting points for each of these repeats. Withineach depressed region the operation is duplicated.

In operation, the carriage is initially motored so that the focal pointof the lens corresponds to the longitudinal position of the previouslydetermined position of the first depression. This position isestablished by the carriage pulse generator 834.

The mandrel is now made to rotate at a constant speed. Circumferentialposition is established by rotational pulse generator 824. The actualrotational speed used will depend on the laser power, desired depth ofcut, laser spot size and carriage advance per revolution. Once themandrel is at operating speed, the computer examines the left-mostcolumn of the bit map for laser instructions. If this column has noblack pixels, the laser will remain off for the entire first revolutionof the mandrel. If there are black pixels in the first column, the laserwill be switched on when the positions on the support membercorresponding to black pixels are positioned at the focal point of thelens. The encoded instructions in this left-most column result inrepeated laser operation around the circumference of the support memberin each of the regions specified to have the pattern repeated.

When a full revolution has been completed, the carriage driverepositions the focal point of the lens to the position of the nextregion of the precursor support member from which material is to beremoved by laser ablation. This new location is directly over thoseregions of the precursor support member corresponding to the pixels inthe second column of the bit map. The new location is verified bycarriage pulse generator 834. The computer then examines the encodedinstructions in the second column of the bit map, and pulses the laseron and off as instructed during the next mandrel revolution. Thisprocess is repeated until the entire pixel pattern in the bit map hasbeen "burned" into the precursor support member.

Note that in the approach, each pass produces a number of narrow cuts inthe material, rather than a large depression. Because these cuts areprecisely registered to line up side-by-side and overlap somewhat, thecumulative effect is a broad depression. Production of a smooth imagerequires that the region established to correspond to an individualpixel in the design be smaller than the minimum laser spot size used.This provides overlap of adjacent passes resulting in subsequentblending of the edges of each pass, and thereby minimizing "jaggies".Though typically square, for some purposes, it is more convenient toemploy pixels of unequal proportions. For example, rectangular pixelsmay be employed.

Recess depth is proportional to power, and inversely proportional torotational speed and carriage advance per revolution. The cumulativeeffect of multiple passes is a wide recess, with blending of detail fromoverlapping passes. This process can be repeated as many times as adesired over the working face of the support member, creating largepattern effects.

If an accent recess is desired, a second pattern is created, identifyingthose pixels to be engraved to a different depth. These follow the sameprocess, but use either a higher laser power or slower rotational speedto achieve increased depth.

There is a surprising and interesting aspect to the above-describedlaser ablation processing of a precursor support member. Unlike a latheturning operation, which would remove material to a constant depth, thelaser ablation process just described removes a fixed amount of materialfrom the precursor support member. For example, in the process justdescribed, the precursor support member comprised the topographicalpattern shown in FIG. 13. The subsequent laser ablation process createsa recessed region corresponding to the mirror image of the letters"JSK". When a nonwoven fabric is made using the finished support member,the letters "JSK" appear in a raised portion of the fabric. This is seenin FIG. 16 where the letters "JSK" comprise first raised portion 16 ofnonwoven fabric 10C. These raised letters "JSK" have the sametricot-like appearance as background portion 12.

EXAMPLE 1

This example shows the production of a topographical support memberwhich can be used to produce nonwoven fabric 10C of FIG. 1C. Theprecursor topographical support member is made of acetal and has thetopographical pattern of peaks, valleys and apertures shown in FIG. 13of the accompanying drawings. The precursor topographical support memberwas made by the laser drilling process disclosed in commonly assignedcopending U.S. patent application Ser. No. 08/307,203 filed Sep. 16,1994, now U.S. Pat. No. 5,585,017 the title of which is "Defocused LaserDrilling Process For Making Fabric Forming Device" and the disclosure ofwhich is hereby incorporated by reference. The support member of thisExample 1 was made on the apparatus of FIG. 16 using the precursorsupport member just mentioned and the laser ablation process describedhereinabove. The precursor support member was mounted on mandrel 821.The computer graphic file used to control the laser ablation process wasthat shown in FIG. 17A. The laser power was set to produce a constantoutput, when on, of 1320 watts. Lens 829 was a positive meniscus lenshaving a focal length of 5 inches. Lens 829 was focused at the topsurface of the unengraved marginal portion of the precursortopographical support member. This coincides with the reference diameterestablished for the precursor support member as explained earlierherein. The rotational speed of mandrel 821 during the laser ablationprocess was 35 rpm, resulting in a support member top surface speed of69 m/min. The carriage advance per revolution was 50 microns. The laserablation process was continued until the entire peripheral surface ofthe precursor support member was laser engraved with the desiredpattern. The resulting topographical support member comprised a firstpattern nearer its outer surface and a second pattern beneath said firstpattern, i.e., recessed into the depth of the support member. The firstpattern in the resulting support member was the pattern illustrated inFIG. 13 of the drawings. The second pattern, i.e., the pattern recessedinto the depth of the support member beneath the first pattern, was thepattern illustrated in FIG. 17A of the drawings.

EXAMPLE 2

This example illustrates the production of nonwoven fabric 10C shown inFIG. 1C using the topographical support member made in accordance withExample 1. The topographical support member of Example 1 was removedfrom mandrel 821 of the apparatus shown in FIG. 16 and was mounted ondrum 90 of the apparatus shown in FIG. 12.

A fibrous web consisting entirely of staple-length cotton fibers andweighing 1.2 ounces per square yard was made by combining a 0.6 ounceper square yard 100% cotton web made by a conventional carding processand a 0.6 ounce per square yard 100% cotton web made by a conventionalair laying process. In the specific example being discussed, the cardedweb and the air laid web were combined by positioning the air laid webon top of the carded web. It will be understood that the carded webcould, if desired, be positioned on top of the air laid web.

The aforementioned 1.2 oz/sq yd 100% cotton web was lightlypre-entangled using a conventional flat-belt entangling apparatuscomprising 18 orifice strips which were spaced from each other in themachine direction of the apparatus and which extended across the widthof the apparatus. The diameter of the orifices was 0.007 inch. Therewere thirty (30) orifices/lineal inch in each orifice strip. Theentangling fluid was water. In going from the upstream direction to thedownstream direction, water was supplied to the first 3 orifice stripsat 200 psig; to the next 3 orifice strips at 600 psig; and to the last12 orifice strips at 1000 psig. The pre-entangling apparatus wasoperated at about 330 feet per minute (fpm). The thus processed cottonweb was dried over steam cans to provide a lightly entangled 100% cottonweb hereinafter called a "pre-bond".

Two plies of the above-described pre-bond were used to make nonwovenfabric 10C. The two-ply pre-bond was placed on the topographical supportmember of Example 1 which had been previously been mounted on mandrel821. The two-ply pre-bond was then sprayed lightly with water. Thedistance from the bottom of the orifice strips of the apparatus shown inFIG. 12 to the top of the pre-bond material was about 0.75 inch. Onlyone of the five orifice strips 92 shown in FIG. 12 was used for theprocessing step. The two-ply pre-bond was passed once under the orificestrip at 100 yards per minute while water was being supplied to orificestrip at a pressure of about 600 psig. The pre-bond was then passedunder the orifice strip eight additional times. The line speed employedduring these eight passes was 100 yards per minute with water beingsupplied to the orifice strip at a pressure of about 1600 psig. Nonwovenfabric 10C thus produced was vacuum de-watered, removed from the supportmember, and dried in a hot air oven.

It will be understood that nonwoven fabric 10C comprised a backgroundportion 12 having a tricot-like appearance which resulted from the firstpattern comprising the support member, said first pattern correspondingto that shown in FIG. 13 of the drawings. Raised portion 16 of thenonwoven fabric 10C resulted from the pattern of FIG. 17A.

Further details respecting nonwoven fabrics of the kinds disclosedherein are found in commonly assigned copending U.S. patent applicationSer. No. 08/308,001, pending filed Sep. 16, 1994, the title of which is"Nonwoven Fabrics Having Raised Portions", and the disclosure of whichis hereby incorporated by reference.

Basis weight is determined as follows. The material to be tested isconditioned for at least 6 hours at 70° F. and a relative humidity of65%. Three individual test specimens are die cut from the desired partof the conditioned material using a die punch of known, pre-determinedarea. This area is on the order of 30 square millimeters. Each die cuttest specimen is weighed on an analytical balance. The basis weight ofeach individual test specimen is calculated by dividing its weight byits known area. The basis weight is reported as the average of the basisweights of the three test specimens.

While several embodiments and variations of the present invention aredescribed in detail herein, it should be apparent that the disclosureand teachings of the present invention will suggest many alternativedesigns to those skilled in the art.

What is claimed is:
 1. A topographical support member for producing anonwoven fabric comprising:a) a body having a top surface including afirst micro-sized topographical pattern; b) a pattern of aperturesextending through said body, each of said apertures having a conical topportion and the center line to center line spacing of adjacent aperturesbeing less than the major diameter of the conical top portion of eachadjacent aperture; and c) at least one macro-sized region of said bodyrecessed below said top surface.
 2. The support member of claim 1wherein said at least one macro-sized region has a second micro-sizedtopographical pattern on a top surface of said region.
 3. The supportmember of claim 2 wherein said first and second topographical patternsare the same pattern.
 4. The support member of claim 1 wherein said atleast one macro-sized region includes a major surface recessed a firstdepth below the top surface and one or more minor surfaces recessed atdepths different from said first depth.
 5. The support member of claim 4wherein said macro-sized region includes one minor surface surroundingsaid major surface, said minor surface being recessed at a depth belowsaid first depth, the width of said minor surface being substantiallyless than the width of said major surface.
 6. The support member ofclaim 1 wherein said first micro-sized topographical pattern includes apattern of a plurality of peaks and valleys, each of said aperturesbeing surrounded by a cluster of said peaks and valleys.
 7. The supportmember of claim 1 wherein said pattern of the plurality of peaks,valleys and apertures being configured to produce a nonwoven fabric withthe appearance of tricot.
 8. The support member of claim 6 wherein saidat least one macro-sized region includes a pattern of a plurality ofpeaks and valleys surrounding each aperture which is the same as saidfirst micro-sized topographical pattern.
 9. The support member of claim1 wherein said first topographical pattern includes a repeating patternof peaks and valleys and wherein the cross-sectional width of saidmacro-sized region is greater than the spacing between the repeat ofsaid repeating pattern.
 10. The support member of claim 1 wherein saidpattern of apertures is a matrix and wherein the cross-sectional widthof said macro-sized regions is greater than the spacing between theapertures in said matrix.
 11. The support member of claim 1 wherein saidfirst topographical pattern includes a repeating pattern of peaks andvalleys and wherein the cross-sectional width of said macro-sized regionis at least two times greater than the spacing between the repeat ofsaid repeating pattern.
 12. The support member of claim 1 wherein saidpattern of apertures is a matrix and wherein the cross-sectional widthof said macro-sized region is at least two times greater than thespacing between the apertures in said matrix.